Mitochondria are called the ‘batteries’ that send power to our body’s cells. They convert energy from food into forms that cells can utilize. Mitochondria contain 0.1% of mitochondrial DNA (mtDNA) which a child inherits exclusively from its mother.
According to a recent article in Global Tech News, inherited changes (mutations) in mtDNA can cause mitochondrial diseases such as ALS and Alzheimer’s, affecting one out of five-thousand individuals. The mutations, caused by a change in a DNA sequence, interfere with mitochondria’s distribution of energy to the cells. The disorders are incurable, generally untreatable, often serious, and even fatal.
Searching For a Cure
Cells contain about one thousand copies of mtDNA. A person’s risk of mitochondrial disease is determined by the percentage of mutated cells in their body.
A general rule would be that sixty percent or more mutated cells could cause disease.
Heteroplasmic describes the presence of both faulty and healthy mtDNA cells, while a cell that has no healthy mtDNA is called homoplasmic.
New Treatments Are on the Horizon
Cambridge University scientists have found that by using gene editing they can modify the mitochondrial genome in mice. This bodes well for correcting the spelling errors in abnormal mitochondrial DNA in order for the cells to once again function efficiently.
A team at Cambridge successfully eliminated abnormal mtDNA in the heteroplasmic cells of mice in 2018. The team replaced the damaged cells with mitochondria that had healthy DNA. Michal Minczuk M.D. explained that an approach to alter mtDNA on an animal had previously been unsuccessful. He also noted that their approach may only be used on heteroplasmic cells, not on homoplasmic cells.
In a recent accomplishment, the scientists used a tool called a mitochondrial base editor to edit mtDNA in live mice. A live virus is transported through the bloodstream and into the cells.
Dr. Pedro Silva-Pinheiro, the study’s first author, commented that the study has proven that scientists can correct spelling errors in damaged mtDNA and produce healthy mitochondria. If scientists are able to reduce defective DNA, then the disease can be treated.
UK scientists have developed a new and complex approach called mitochondrial replacement therapy. The therapy replaces a mother’s damaged mitochondria with the mitochondria of a healthy donor. Thus far the technique has been minimally successful.
Looking Forward
Dr. Minczuk added further that the scientists have a long road ahead in developing a treatment. However, he is encouraged by the potential for improving mitochondrial replacement therapy and repairing defective mitochondria.
